Mobile devices capable of using many wireless access protocols are currently entering the marketplace. For example, phones will soon be available that can access multimedia services by either a third generation cellular network or a Wi-Fi network based on the IEEE 802.11 series of standards. FIG. 1 shows this graphically. Mobile device 10 uses a radio access network 12 (e.g., a cellular access network based on cdma2000) to access a multimedia application or service 14 in a multimedia enabled core network 16. Alternatively, mobile device 20 can use another wireless access network 22, such as a Wi-Fi network, to access the multimedia application or service 14 via the Internet 24. Typically, these mobile devices 10, 20 are programmed to select the access network used based on availability and a preference setting. For example, a multi-protocol phone or other mobile device may be programmed to select a Wi-Fi network when it is available and the cellular network when no Wi-Fi connection is available.
IP multimedia services include a variety of multimedia applications and/or services such as Voice over IP (VoIP), streaming video, etc. that operate over Internet Protocol (IP) or IP based protocols. With the growing popularity of VoIP clients that execute over a variety of operating systems, authorization schemes for VoIP and other IP multimedia services are required to minimize the potential revenue losses to the access provider resulting from the delivery of IP multimedia services to unauthorized mobile devices.
In wireless mobile access networks and core networks, the Session Initialization Protocol (SIP) is generally used for call control associated with IP multimedia services. In an IP multimedia enabled core network (such as core network 16), the Quality of Service (QoS) constraints identified by the IP multimedia services are authorized based on the policies that are applicable to a specific access network (e.g., radio access network 12, wireless access network 22). The IP multimedia enabled core network provides the call control and services that are delivered to the mobile device (e.g., 10, 20) over one or more different types of access technologies, such as cdma2000, WLAN, etc.
In the existing mobile packet data systems, schemes for limiting the use of access network resources for unauthorized IP multimedia services (e.g., unauthorized VoIP) are required to minimize the potential for revenue loss. While SIP Proxies can be used to minimize potential revenue losses (e.g., from unauthorized VoIP service) over specific access networks, the SIP Proxies should not globally restrict access to free services that may be available over the public Internet.